I have a 1998 Ram 1500, 4wd, 5.2 motor, manual transmission truck. I replaced the passenger side u-joint and upper ball joint yesterday. It has been several years since I have done this kind of work, so I watched a couple of videos on youtube to refresh my memory. Everything seemed to go fine, I replaced both parts and re-assembled everything without any problems. The drive shaft inserted easily.

The 4WD light came on when I started the truck, even though it was not in four wheel drive and four wheel drive does not seem to engage in either 4L or 4H. Four wheel drive operation worked correctly over the winter, so I am assuming something went wrong in the CAD when I inserted the drive shaft.

Can anyone tell me what to look for or test on the CAD? Thanks for your help.

 

The collar that connects the axle
could have moved and not be sliding
with the CAD fork or stuck.

 

Gonna have to pull the cad housing off, and see where things are at. Careful, the little bolts like to break...... Make sure everything is where it should be, if not, put it back where it needs to be. Should be obvious what's up when you get the housing off.

 

I jacked up the truck this morning so all 4 wheels were off the ground. The 4WD shift seems to be working fine. In 2H, the rear wheels turn. In 4L and 4H, the rear wheels and the front left turn correctly, but the front right turns slowly and can be stopped easily by hand.

This makes me think that Tim is probably correct and the collar is the culprit. I'm going to open up the CAD housing and make sure that everything moves freely.

 

I got the CAD housing off, breaking the heads off the two bottom bolts. With the heads up from HeyYou and since the bolts were little more than rust, this did not surprise me. I got the broken bolts out and I'm going to see if I can get some stainless bolts to replace them.

It turns out that the collar is not the problem, it moves freely and completely engages. The shift fork will twists slightly from side to side, but cannot be slid by hand.

How can I test if the shift fork and motor are working correctly? Can I start up the truck and put it in 4W drive with the CAD housing off?

 

Turns out I cracked the housing getting it off the two broken bolts. After removing the indicator switch, I was able to tap on the actuator rod and free it up, but one of the vacuum connectors was rusted through, so it practically fell off. That was probably the original problem. So I ordered a new actuator, housing and indicator switch, but I was able to salvage the fork. The new parts arrive on Tuesday, so hopefully, I will be able to put everything back together again and have a fully functional truck again.

 

Sounds like you found the source of your problem...... test it when you get it back together, and the remember to tell us it's fixed.

 

After putting everything back together with the new parts, my 4WD is working correctly. Thanks for everyone's help.